1. Technical Field
This disclosure relates to an analog-digital conversion system and a method for controlling the same.
2. Related Art
Auto-zeroing techniques function to reduce noise and/or offset voltages in an analog-to-digital converter (ADC). According to such techniques, the input to an amplifier in an ADC circuit's be interrupted and connected to a constant potential. In this state, an offset voltage and a low frequency noise (e.g., flicker noise (1/f noise) and the like), can be sampled by a capacitor provided on the output side or the input side of the amplifier circuit separately from the ADC. This sample can then be used to reduce or eliminate noise and/or unwanted offset voltages.
Sometimes, however, it can be difficult to reduce the effect of a relatively high frequency noise having a shorter cycle than the sampling time on the capacitor provided between the amplifier circuit and the ADC or the sampling time on the capacitor in the ADC. Moreover, some auto-zeroing techniques require adding a capacitor for sampling the offset voltage and the noise and a period for sampling such undesirable signal components. Additionally, a low-pass filter may be required in some instances thereby, increasing the complexity of the circuit and the required. It is desirable to reduce or eliminate these problems.